 /*******************************************************************************
  * Copyright (c) 2004, 2006 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.core.internal.runtime;

 import java.io.*;
 import java.net.URL ;
 import java.net.UnknownServiceException ;
 import org.eclipse.core.internal.boot.PlatformURLConnection;
 import org.eclipse.core.internal.boot.PlatformURLHandler;
 import org.eclipse.osgi.service.datalocation.Location;
 import org.eclipse.osgi.util.NLS;

 public class PlatformURLConfigConnection extends PlatformURLConnection {
     private static final String FILE_PROTOCOL = "file"; //$NON-NLS-1$
 private static boolean isRegistered = false;
     public static final String CONFIG = "config"; //$NON-NLS-1$

     private boolean parentConfiguration = false;

     /*
      * Constructor for the class.
      */
     public PlatformURLConfigConnection(URL url) {
         super(url);
     }

     /* (non-Javadoc)
      * @see org.eclipse.equinox.internal.url.PlatformURLConnection#resolve()
      */
     protected URL resolve() throws IOException {
         String spec = url.getFile().trim();
         if (spec.startsWith("/")) //$NON-NLS-1$
 spec = spec.substring(1);
         if (!spec.startsWith(CONFIG))
             throw new IOException(NLS.bind(CommonMessages.url_badVariant, url.toString()));
         String path = spec.substring(CONFIG.length() + 1);
         // resolution takes parent configuration into account (if it exists)
 Activator activator = Activator.getDefault();
         if (activator == null)
             throw new IOException(CommonMessages.activator_not_available);
         Location localConfig = activator.getConfigurationLocation();
         Location parentConfig = localConfig.getParentLocation();
         // assume we will find the file locally
 URL localURL = new URL (localConfig.getURL(), path);
         if (!FILE_PROTOCOL.equals(localURL.getProtocol()) || parentConfig == null)
             // we only support cascaded file: URLs
 return localURL;
         File localFile = new File(localURL.getPath());
         if (localFile.exists())
             // file exists in local configuration
 return localURL;
         // try to find in the parent configuration
 URL parentURL = new URL (parentConfig.getURL(), path);
         if (FILE_PROTOCOL.equals(parentURL.getProtocol())) {
             // we only support cascaded file: URLs
 File parentFile = new File(parentURL.getPath());
             if (parentFile.exists()) {
                 // parent has the location
 parentConfiguration = true;
                 return parentURL;
             }
         }
         return localURL;
     }

     public static void startup() {
         // register connection type for platform:/config handling
 if (isRegistered)
             return;
         PlatformURLHandler.register(CONFIG, PlatformURLConfigConnection.class);
         isRegistered = true;
     }

     /* (non-Javadoc)
      * @see java.net.URLConnection#getOutputStream()
      */
     public OutputStream getOutputStream() throws IOException {
         if (parentConfiguration || Activator.getDefault() == null || Activator.getDefault().getConfigurationLocation().isReadOnly())
             throw new UnknownServiceException (NLS.bind(CommonMessages.url_noOutput, url));
         //This is not optimal but connection is a private instance variable in the super-class.
 URL resolved = getResolvedURL();
         if (resolved != null) {
             String fileString = resolved.getFile();
             if (fileString != null) {
                 File file = new File(fileString);
                 String parent = file.getParent();
                 if (parent != null)
                     new File(parent).mkdirs();
                 return new FileOutputStream(file);
             }
         }
         return null;
     }
 }

